The disclosure of Japanese Patent Application No. 11-142137 filed on May 21, 2000 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to a multiple spindle processing unit for simultaneously processing a plurality of processing locations of a work.
2. Description of the Related Art
As an example of such a multiple spindle processing unit, Japanese Utility Model Publication No. HEI 55-21835 discloses a multiple spindle head wherein a plurality of cylindrical housings journaling tool main spindles are removably secured to a case so as to easily contend with a modification made to a work. In this multiple spindle head, an end of a drive shaft journaled in a body for securing the case to an opening end surface is connected to ends of the tool main spindles by means of gears, and all the tool main spindles are driven by a single motor.
This multiple spindle head makes it possible to contend with a modification made to a work by arranging the housings journaling the tool main spindles at positions corresponding to processing locations of the work. However, a great deal of labor and craftsmanship are required to arrange the gears and determine the number of gears such that the tool main spindles arbitrarily arranged in accordance with the processing locations of the work are driven in a desired rotational direction and at a desired rotational speed. Further, such a modification leads to problems such as an increase in the number of required parts, complication of assembly operations, a resultant increase in costs, and undesirable maintainability. Outwardly extending flanges are formed at openings of the housings. The housings are fastened at the flanges to the case by means of bolts. Therefore, the minimum distance among the tool main spindles cannot be reduced beyond a certain limit, and in some cases, it is impossible to handle a work whose processing locations are close to one another.
It is an object of the present invention to solve such problems. According to the present invention, there is provided a multiple spindle processing unit comprising a housing, a main spindle which is coaxially and rotationally journaled by the housing and which has a front end portion where a chuck for mounting a tool is provided, a plurality of tool main spindle assemblies each composed of a built-in motor which is built into the housing to rotationally drive the main spindle, and a frame member which is guided and supported so as to be moved towards or away from a work and which has insertion holes for removably mounting the tool main spindle assemblies at a plurality of locations corresponding to a plurality of processing locations of the work. The built-in motors for rotationally driving the main spindles are built into the housings correspondingly. Therefore, in order to change arrangement of the main spindles in response to a change in processing locations of the work, it is required just to replace the insertion holes formed in the frame member with those corresponding to the processing locations of the work and rearrange the tool main spindle assemblies journaling the main spindles.
The multiple spindle processing unit may further comprise a holding plate which is divided into a plurality of portions and which securely sandwiches the housing of each of the tool main spindle assemblies. The tool main spindle assembly may removably be mounted to the frame member through the holding plate with the housing inserted through the insertion hole. This construction makes it possible to arrange the tool main spindle assemblies very close to one another.
Furthermore, in the multiple spindle processing unit, a flange may integrally be formed to radially protrude from an outer peripheral surface of the housing of each of the tool main spindle assemblies, and the tool main spindle assembly may removably be mounted to the frame member through the flange with the housing inserted through the insertion hole. This construction dispenses with a separate holding plate.
In the multiple spindle processing unit, some of the tool main spindle assemblies may be mounted to the frame member with the flange in close contact with one side surface of the frame member, and the other tool main spindle assemblies may be mounted to the frame member with the flange in close contact with the other side surface of the frame member. In this case, the flanges located on opposed sides of the frame member do not interfere with each other.
In the multiple spindle processing unit, the flange may be formed to protrude from the housing on diametrically opposed sides. In this construction, the width of the flange can be reduced in the direction perpendicular to the direction in which the flange protrudes.